Prior to covid, SW was releasing their schedule approx 8 months out. That has all changed now, with schedules only available out 6 months, or so. I don't think we're going to see that change anytime soon.
Currently, I wouldn't assume that any historical data you see regarding schedule releases is, or will be, a good predictor of the future. I don't expect we'll see Sept schedules until March/April.
Steve